That degree symbol is causing the issue. It also makes the fieldtype as "TEXT", whereas the acceptable fieldtype for X and Y field should be numeric (Float, Double, etc.).
If possible, remove the degree symbols in the excel file itself, and ensure the cell format is "numeric".
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Alternatively, you may add two more fields, X and Y (Float or Double) in the geodatabase table, and use Field Calculator to input the values of Longitude and Latitude in them respectively.
Following would be the expression in Field Calculator (Python Parser)
X
!Longitude!.split("°")[0]
Y
!Latitude!.split("°")[0]
Think Location